Unit 21 Quiz

In most cases, the refrigerant leaving the evaporator must be _____ percent vapor.

Answer : 100

As a rule of thumb, the temperature of the evaporator should be about ___°F colder than the box temperature.

Answer : 15 Degree's

SEER is calculated based on the total amount of ____ the system will provide over theentire season, divided by the total number ______ it will consume.

Answer : Cooling,Watts-Hours

Every central split cooling system manufactured in the USA today must have a Seasonal Energy Efficiency Ratio (SEER) of at least 10.

Answer : False

The device used to feed refrigerant to multiple circuits in an evaporator is called a flow control.

Answer : False

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Answer : Hot Gas Defrost

The two primary functions of an evaporator are to remove __________ and_________ from the refrigerated space.

Answer : Moisture,Heat

A stamped plate evaporator usually does not use a fan to move air across it.

Answer : True

Fewer fins per inch on an evaporator allow more ice to build between defrost cycles.

Answer : True

The refrigerant in the evaporator must be colder than the air passing over it for heat to transfer to the evaporator.

Answer : True

When the velocity of the air moving over an evaporator is slow, the "air film" acts as an insulator and slows the rate of heat exchange.

Answer : True

If an evaporator has a pressure drop of 10 psig and the low side pressure is 15 psig, what is the pressure at the inlet of the evaporator?

a. 10 psig b. 25 psig c. 15 psig d. 5 psig Answer : B

A typical super-heat for an evaporator operating under normal conditions would be ?

a. 14-16 degrees b. 4-6 degrees c. 8-12 degrees d. 6-8 degrees Answer : C

A typical evaporator operating temperature in an air-conditioning system is ____.

a. 40°F b. 55°F c. 75°F d. 200°F ANSWER : A

If an R-12 refrigeration system is operating with a 25.4 psig suction pressure, what is the evaporator superheat if the evaporator outlet temperature is 34°F?

a. 9°F b. 59°F c. 34°F d. 25°F ANSWER : A

If a low temperature evaporator is forming excess ice, which of the following could be a possible problem?

a. The evaporator fan motor is defective. b. The unit is not staying in defrost long enough. c. The defrost heater is defective. d. All of the above are correct. Answer : D

If a high temperature evaporator is forming ice, which of the following is a possible problem?

a. evaporator fan not running b. compressor not running c. condenser fan not running d. no problem, ice formation normal Answer : A

A forced draft high temperature evaporator would ____.

a. have its fins very close together b. not need to be defrosted c. need a hot gas defrost d. both a and b ANSWER :D

A refrigeration system designed for the storage of flowers or candy is considered a ____ type.

a. high temperature b. medium temperature c. low temperature d. sharp freezing Answer : A

A large capacity evaporator would probably have ____.

a. stainless steel tubing b. an excess of liquid refrigerant c. an excess of vapor refrigerant d. multiple refrigerant circuits Answer : D

The capacity of an evaporator is affected by ____.

a. the saturation pressure of the low side of the system b. the saturation pressure of the high side of the system c. the amount of evaporator superheat d. all of the above ANSWER : D